Two-step electrosynthesis and catalytic activity of CoO−CoO • xH<inf>2</inf>O-supported Ag, Au, and Pd nanoparticles

© 2020, Springer Science+Business Media LLC. Two-step electrosynthesis of CoO-CoO•xH2O-supported metal nanoparticles (MNPs, M = Au, Ag, Pd) was carried out in N,N-dimethylformamide in the absence and in presence of poly(N-vinylpyrrolidone) (PVP) using atmospheric oxygen as both a reagent and a mediator at potentials of its reduction to a superoxide radical anion. In the first step, oxygen reduction in the presence of Co2+ ions added to the solution as a salt or generated by dissolving the Co-anode during electrolysis produces a mixture of cobalt oxide CoO and its hydrated form CoO-CoO • xH2O (CoOxHy). When Ag+, Au+, Pd2+ ions are added to the obtained solution of CoOx H y, a redox reaction between CoO and the metal ion gives the MNPs and CoO+. In the second step, oxygen-mediated electroreduction of CoO+ serving as the second mediator is carried out, and the redox reaction is completely shifted towards the formation of MNPs. In the absence of PVP, AgNPs (18±4 nm) bind and stabilize completely in the CoOxHy matrix, PdNPs (6±1 nm) stabilize only partially, and AuNPs (21±10 nm) do not bind and, therefore, only their agglomerates are obtained (~200 nm). In the presence of PVP, individual AgNPs (5±2 nm), AuNPs (13±5 nm), PdNPs (3±1 nm) are stabilized in the PVP shell and are bound by the matrix. The obtained nanocomposites M/CoOx H y and M@PVP/CoOxHy catalyze the reduction of p-nitrophenol with sodium borohydride in an aqueous medium. Their catalytic activity is due to MNPs; CoOx H y acts as an inert matrix

Photocatalytic properties of hybrid materials based on a multicharged polymer matrix with encored TiO<inf>2</inf>and noble metal (Pt, Pd or Au) nanoparticles

© The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2020. In this study, we report a synthesis of new nanocomposites, wherein TiO2is introduced into multicharged polymeric matrix and covered with noble metals (Pt, Pd or Au) for the photocatalytic application. A photocatalytic activity investigation was performed by studying the degradation of methylene blue. It revealed that all obtained nanocomposites demonstrate enhanced photocatalytic ability when compared to pure TiO2, under both UV (24 °C) and solar light (−2 °C). The morphology and catalytic properties of the composites depend on the noble metals. The kinetic speed value of photodegradation was found to increase in the following sequence: TiO2< TiO2-NPst ≈ Pd-TiO2@NPSt < Pt-TiO2@NPSt ≈ Au-TiO2@NPSt

Polymer and supramolecular nanocontainers based on carboxylate derivatives of resorcinarenes for binding of substrates and design of composites for catalysis

© 2020, Springer Science+Business Media LLC. The work describes the synthesis of supramolecular and polymer nanocontainers based on carboxylate resorcinarene derivatives. A comparative analysis of their inclusive characteristics toward hydrophilic and hydrophobic substrates was carried out. The obtained containers and silver nanoparticles were used to develop composite materials, and their catalytic activity in the reduction of {tip}-nitrophenol was examined. It was shown that polymer nanocontainers are more ef cient in binding organic substrates, while the supramolecular containers are more suitable for the design of catalytically active composites. The reduction of {tip}-nitrophenol in the presence of nanocomposites based on supramolecular containers proceeds with a higher rate and does not show an induction period

Doxorubicin delivery by polymer nanocarrier based on N-methylglucamine resorcinarene

© 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group. Herein we describe a simple method for the synthesis of polymer nanocarrier for the doxorubicin delivery. The nanocarrier consists of N-methyl-glucamine resorcinarenes that are covalently bound to phenylboronic acid. The nanocarrier is stable at normal pH but is hydrolysed at pH below 6. It demonstrates low cytotoxicity and haemolytic activity. Doxorubicin was successfully loaded into the nanocarriers cavity and its release occurs at pH. Flow cytometry data showed that the carrier improves the penetration of doxorubicin into M-Hela cancer cell lines. The encapsulated doxorubicin demonstrates higher cytotoxicity towards the cancer cells